A channel estimation sequence including two concatenated sequences (S and G) respectively including two complementary sequences (s and g), which are extended periodically by extensions (esf, esd and egf, egd) which constitute copies of their starting part and/or ending part and which are respectively concatenated at the end and/or start of the sequence. Also, a channel estimation method including transmitting the channel estimation sequence and receiving and correlating the received signal with the first complementary sequence (s), correlating the received signal with the second complementary sequence (g), adding the results of the two correlations.